Excel VBA - Floor on Column's Used Rows - vba

Question

I am trying to convert the used range of a column to hourly data using floor.
As a function in Excel I have =FLOOR(A2, "1:00")
So 2016-07-01 07:59:59.0000000 would become 01-07/2016 7:00
I would like to do this in VBA for just Column A where the first row is a header. I guess I'd need to convert to dateTime afterwards to but haven't thought about that yet (shouldn't be difficult).
I have tried this:
.Range(Cells(2, 1), Cells(Rows.Count, 1).End(xlUp)) = _
Application.WorksheetFunction.Floor(Cells(2, 1), Cells(Rows.Count, 1).End(xlUp), "1:00")
But get wrong number of arguments error.
This:
.Range("A:A") = Application.WorksheetFunction.Floor("A:A", "1:00")
gives a type mismatch.
Not sure how to proceed.

Answer 1

The WorksheetFunction.Floor Method in VBA is a little different from the worksheets =Floor function:
WorksheetFunction.Floor(Arg1, Arg2)
Both arguments Arg1 and Arg2 need to be of the type double.
So you will need to use 1/24 instead of "1:00" (which is the same because 1 hour is 1/24 of a day) and a value .Cells(i, "A").Value instead of a cell reference name "A:A".
Also you will need a loop to achieve it for every used cell in the whole column A.
Option Explicit 'First line at your module ensures you declare any variables
Public Sub FloorFormat()
Dim lastRow As Long
With Worksheets("Sheet1") 'Your sheet name here
lastRow = .Range("A" & .Rows.Count).End(xlUp).Row 'find last used row
Dim i As Long
For i = 1 To lastRow 'do the following for all used rows in column A
.Cells(i, "A").Value = Application.WorksheetFunction.Floor(.Cells(i, "A").Value, 1 / 24)
Next i
End With
End Sub